Furnace



Oct. 15, 1929. G. NAISMlTH ET AL 1,732,138

FURNACE Filed Dec. 19, 1927 '3 Sheets-Sheet 1 605 rq/r Producis of Combysiion.

Oct. 15, 1929.

G. NAISMITH ET AL FURNACE 3 Sheets-Sheet File d Dec. 19, 1927 INVENTOI QS Mama;

Oct. 15, 1929. G. NAISMITH ET AL 1,732,138

FURNACE Filed Dec. 19, 1927 s Sheets-Sheet 5 CD CD Q Q C CD Q QQCDCDCDCDQCD INVENTORS Patented Oct. 15, 1929 UNITED STATES.

GEORGE NAISMITH AND DONALD M. NAISMITH, OF PITTSBURGH, PENNSYLVANIA FURNACE Application filed December 19, 1927. Serial No. 241,015.

Our invention is an improvement in heating furnaces of the recuperative type particularly adapted to the heating of ingots and the like, Within a soaking pit or chamber. 1 It has in view to provide a recuperative furnace construction in which the fuel gases are brought together in a common vertical mixing well orchamber for combination with pre-heated air and then introduced horizonlo tally into a common mixing, combustion and delivery chamber, with resulting circulation through the heating chamber of the furnace. The combustion gases thus combined enter at one side of the heating chamber, pass across and down into and then upwardly therethrough and finally emerge from the" heating chamber at the same side, above the inlet opening and then outwardly and down through the waste gas passages in the mass 2c of recuperative checkerwork.

llhe construction has in view to provide in a furnace construction of such t pe, means for utilizing practically all of the Waste heat for pie-heating of the incoming air in a 2 direct, economical and effective manner; also 4 to utilize'the gases of combustion most effectively and directly inwardly, upwardly and outwardly, through and within the heating chamber, and to provide a simple, economical so and easily built and repaired furnace con-= struction of the type involved.

lln the drawings showing one preferred embodiment of the invention:

Fig". l is a longitudinal vertical section through the furnace on'the line I-I of Fig.

2, artly broken away at each end;

b line lll-e-lll of Fig. 1;

Fig. 3 is a vertical section on the line fill-Jill of Fig. 2;

Fig. 4 is a perspective view of one of the circulating refractory blocks. 2 The soaking pit or heating chamber 2 of the furnace is of generally rectangular construction within s1de walls 3-3 and outermost end walls 4-5.

The construction of the furnace is rec tangular as shown, preferably of uniform width from end to end, providing continuous side walls, between which are located .the ele i 2 is a horizontal. sectional view on the vated heating chamber and the recuperative construction for pre-heating, combination, combustion and exhaust of the gases.

Inwardly beyond end Wall 4, of the furnace chamber proper, is a main supporting an enclosing inner wall 6, beyond which the heating chamber 2 extends by a floor 7 carried on suitable framing 32, as will be readily understood.

Inwardly beyond inner end wall 6 is a transverse apertured partition wall 7 through which pre-heated gas and air pass into a common interveningvertical well or chamber -8. The latter extends upwardly from the bottom foundation to substantially the full height of wall 7 and leads over by horizontal extension 9 into the lower portion of heating furnace hamber 2, and across the full inner Width thereof.

Wall 6 extends slightly above floor ,7 in the manner of a bridge Wall 10, over which the fuel, gases in combustion pass, the wall being preferably beveled inwardly and downwardly to allow for the free passage of the expanding gases of combustion into the full lower body portion of the heating chamber.

The upper portion of well 8 is covered by a horizontal partition 11 laid across from one side to the other and separating the incoming gas and air passage 9, from the upper outgoing waste gas passage 12. Said passage or space 12 extends from the upper portion of the heating chamber 2, above incoming channel 9, outwardly along the full upper length of the furnace over to an oppositeinner confining wall 13.

Said wall, with wall 7, and side walls 3, provide the checkerwork-containing recuperator chamber which occupies the full length and Width between said walls. and from the bottom to the top, as shown in Fig. 1.

Waste gas passage 12 extends for the full length of the recuperator chamber and the additional distance over to'the heating chamher 2, and is covered by an arched roof 14, conlining the outgoing gases in their passage, as indicated.

Heating chamber 2 is covered by a suitable closing cover 15 of any suitable construction, adapted to be moved away for insertion and removal of the ingots or other articles to be heated.

The recuperative chamber is filled with a body of pre-heat-ing brick or tile 16, shown in detail in Fig. 4:. These are of special con struction, and are open from end to end by a 7 horizontal circulating channel 17 for passage therethrough of either air or combustion gases, as they may be used.

Alternating rows of the blocks are laid up close together with the openings 17 forming continuous series in such a manner as to provide continuous horizontal air and gas circulating and heating passages. These registervwith similar inlet openings 18 in wall ward and outward circulation of waste gases,

as shown in Fig. 2. The alternating single br cks between each contlnuous row of bricks leaves a series of intervening vertical circulating spaces 20 and the horizontal openings 17 of the single unit bricks for the outgoing waste gases towards the stack.

By such arrangement the incoming air passes through each continuous upper series of openings 17 to chamber 8, and is in intimate heating relationship with the outgoing waste gases, thereby becoming highly heated and ready for combination with the fuel gas in chamber 8.

Air is furnished to openings 18 for such circulation from a common supply chamber '21-to which air is furnished from the atmosphere by any suitable means, as aconduit 22.

Vertically below air chamber 21 and partition 31 is the gas supply chamber 23, to which gas is furnished from any source, for similar pie-heating through a similar series of hori zontal channels 1817-19, extending from one end of the recuperative chamber to the other, and into the lower portion of chamber 8, for combination with the upper incoming hot air. i

The several horizontal series of bricks are spaced apart and maintained in supported position by transverse bridge strips or bars 24, spaced apart longitudinally in each tier to provide clearance openings corresponding to the vertical openings 20.

By such arrangement the series of continuous down going waste gas conduits 20 are provided, with the communicating individual cross openings 17, so that all of the waste gases will pass downwardly and horizontally, arriving finally at the common outlet chamber 25 communicating by flue 26 with the stack.

Supporting arches 27 provide intervening channels 28 registering with and leading downwardly from the several circulation spaces 20, providing ample circulation clearance, as will be readily understood.

The incoming gas and air mixing chamber 8 is provided with a bottom collecting cavity 29 closed by a removable gate or wall 30 for removal of any accumulated cinders or other waste products of combustion.

The construction and manner or" operation of our improved furnace will be readily understood and appreciated from the foregoing description.

The supply of air and gas are under the control of the operator by any suitable valve or gate mechanism, and the furnace may be operated continuously, avoiding the necessity of the usual reversal of circulation and with resulting regularity of operation. The temperature may be continuously maintained to the desired degree, and the articles to be heated are exposed to the upwardly circulating gases within the closed chamber for any desired time.

The heating chamber itself may be of any desired proportions, but for best results the incoming fuel gases in combustion first pass downwardly toward the bottom, then up through the whole interior, and outwardly from a higher level, with thorough action on the contained units, as ingots, etc.

What we claim is:

1. A furnace having an outwardly enclosed heating chamber and provided with laterally continuous inlet and outlet ports for heating gases located at different levels on the inner side of said chamber to cause all of the gases to pass inwardly across the hearth and then upwardly and outwardly through the chamber, and having a vertical mixing chamber communicating with incomingair and gas and with the inlet port leading to the heating chamber.

2. A furnace having an outwardly extending entirely enclosed heating chamber provided at its inner side with a lower laterally continuous inlet port and an upper laterally continuous outlet port for heating gases and a longitudinally extended waste gas passage of substantially the width of the chamber, said inlet and outlet ports to and from the heating chamber being above and below the hearth and roof of the chamber respectively.

3. A furnace having an entirely enclosed heating chamber provided with a lower inlet po rt for incoming gases and an upper outlet port for outgoing gases on the inner side of the chamber, the lower port being above a bottom wall and having oppositely disposed downwardly sloping faces.

4. A furnace having an enclosed heating chamber provided at its inner side with a lower inletport, a Vertically arranged mixing chamber extending. downwardly therefrom, means providing channels for introducing air and'gas to the mixing chamber,

an upper outlet port leading inwardly from the heating chamber and having a waste gas passage extension, and means providing circulation of waste gases from the said wastepassageways leading from the outlet port for waste gases.

6. A furnace having an enclosed heating chamber provided at one side with a lower inlet port and an upper outlet port, a vertically arranged mixing chamber opening at the top to the lower inlet port, and a recuperator having individual horizontal passageways leading-to the mixing chamber for gases to be heated and intervening vertical and horizontal passageways between said passageways leading from the outlet port for waste gases to a gas outlet conduit.

7. A furnace having an enclosed heating chamber provided at one side with alower inlet port and an upper outlet port, a vertically arranged hot :air and gas mixing chamber leading to the inlet port, an upper waste gas chamber leading from the outlet port, a' lower waste gas outlet conduit, and

a9- recuperator between the upper waste gas chamber and the lower outlet conduit having series of individual horizontal air and gas passageways leading to the mixing chamber and intervening reverse circulation passages leading from the waste gas chamber to the gas outlet conduit.

' In testimony whereof we hereunto afiix our signatures.

' GEORGE 'NAISMITH.

DONALD M. NAISMITH. 

